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Diffstat (limited to 'doc/crypto/EVP_DigestSignInit.pod')
| -rw-r--r-- | doc/crypto/EVP_DigestSignInit.pod | 87 |
1 files changed, 0 insertions, 87 deletions
diff --git a/doc/crypto/EVP_DigestSignInit.pod b/doc/crypto/EVP_DigestSignInit.pod deleted file mode 100644 index 83e65894d9d9..000000000000 --- a/doc/crypto/EVP_DigestSignInit.pod +++ /dev/null @@ -1,87 +0,0 @@ -=pod - -=head1 NAME - -EVP_DigestSignInit, EVP_DigestSignUpdate, EVP_DigestSignFinal - EVP signing functions - -=head1 SYNOPSIS - - #include <openssl/evp.h> - - int EVP_DigestSignInit(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx, - const EVP_MD *type, ENGINE *e, EVP_PKEY *pkey); - int EVP_DigestSignUpdate(EVP_MD_CTX *ctx, const void *d, size_t cnt); - int EVP_DigestSignFinal(EVP_MD_CTX *ctx, unsigned char *sig, size_t *siglen); - -=head1 DESCRIPTION - -The EVP signature routines are a high level interface to digital signatures. - -EVP_DigestSignInit() sets up signing context B<ctx> to use digest B<type> from -ENGINE B<impl> and private key B<pkey>. B<ctx> must be initialized with -EVP_MD_CTX_init() before calling this function. If B<pctx> is not NULL the -EVP_PKEY_CTX of the signing operation will be written to B<*pctx>: this can -be used to set alternative signing options. - -EVP_DigestSignUpdate() hashes B<cnt> bytes of data at B<d> into the -signature context B<ctx>. This function can be called several times on the -same B<ctx> to include additional data. This function is currently implemented -usig a macro. - -EVP_DigestSignFinal() signs the data in B<ctx> places the signature in B<sig>. -If B<sig> is B<NULL> then the maximum size of the output buffer is written to -the B<siglen> parameter. If B<sig> is not B<NULL> then before the call the -B<siglen> parameter should contain the length of the B<sig> buffer, if the -call is successful the signature is written to B<sig> and the amount of data -written to B<siglen>. - -=head1 RETURN VALUES - -EVP_DigestSignInit() EVP_DigestSignUpdate() and EVP_DigestSignaFinal() return -1 for success and 0 or a negative value for failure. In particular a return -value of -2 indicates the operation is not supported by the public key -algorithm. - -The error codes can be obtained from L<ERR_get_error(3)|ERR_get_error(3)>. - -=head1 NOTES - -The B<EVP> interface to digital signatures should almost always be used in -preference to the low level interfaces. This is because the code then becomes -transparent to the algorithm used and much more flexible. - -In previous versions of OpenSSL there was a link between message digest types -and public key algorithms. This meant that "clone" digests such as EVP_dss1() -needed to be used to sign using SHA1 and DSA. This is no longer necessary and -the use of clone digest is now discouraged. - -For some key types and parameters the random number generator must be seeded -or the operation will fail. - -The call to EVP_DigestSignFinal() internally finalizes a copy of the digest -context. This means that calls to EVP_DigestSignUpdate() and -EVP_DigestSignFinal() can be called later to digest and sign additional data. - -Since only a copy of the digest context is ever finalized the context must -be cleaned up after use by calling EVP_MD_CTX_cleanup() or a memory leak -will occur. - -The use of EVP_PKEY_size() with these functions is discouraged because some -signature operations may have a signature length which depends on the -parameters set. As a result EVP_PKEY_size() would have to return a value -which indicates the maximum possible signature for any set of parameters. - -=head1 SEE ALSO - -L<EVP_DigestVerifyInit(3)|EVP_DigestVerifyInit(3)>, -L<EVP_DigestInit(3)|EVP_DigestInit(3)>, L<err(3)|err(3)>, -L<evp(3)|evp(3)>, L<hmac(3)|hmac(3)>, L<md2(3)|md2(3)>, -L<md5(3)|md5(3)>, L<mdc2(3)|mdc2(3)>, L<ripemd(3)|ripemd(3)>, -L<sha(3)|sha(3)>, L<dgst(1)|dgst(1)> - -=head1 HISTORY - -EVP_DigestSignInit(), EVP_DigestSignUpdate() and EVP_DigestSignFinal() -were first added to OpenSSL 1.0.0. - -=cut |